Magnetoelastic superstructure in a ferromagnetic film

A study is made of a magnetoelastic (ME) superstructure in a film of a unia xial ferromagnet with the easy magnetization axis parallel to its surface. The existence of the spatially modulated phase is determined entirely by th e magnetostriction coupling of magnetization to lattice deformation at the ferromagnet-substrate interface. In the vicinity of the second-order magnet ic orientational phase transition (OPT) induced by an external magnetic fie ld H the static distribution of magnetization and elastic strain in the dom ain phase is found to be closed to the distribution for the critical Love m ode in the homogeneous phase. Apart from the OPT the width of domains incre ases drastically with H decreasing. It is shown that the singular defects ( dislocations and disclinations) appear in the regular domain structure in t he vicinity of the OPT, and such defects destroy the long-range order in th e ME superstructure. The calculation is extended to ME superstructures in a film of a two-sublattice orthoferrite.